Altitude sensing systems for flying height adjustment

Abstract

An altitude sensor includes a support frame and a sensor unit mounted in the support frame. The support frame has an upper shield and a lower shield. The sensor unit includes a beam and a damper. The damper is configured to move up and down in response to the air flow, which drives the beam to move up and down accordingly. Distances from the damper to the upper shield and the lower shield are less than those from the beam to upper shield and the lower shield. The altitude sensor possesses super specific properties such as unlimited sensitivity to flying height because of no size constraints and unchanged sensitivity under a changing environment, a selfprotective mechanism to resist deformation in case of an accident, easy manufacture process as well as low production cost. The present invention also discloses an altitude sensor for use in a disk drive device and a disk drive device with the altitude sensor.

1. An altitude sensor configured to detect an air flow generated by a component of a system, comprising:
 a support frame having an upper shield and a lower shield opposite the upper shield; 
 a sensor unit mounted in the support frame, the sensor unit comprising: 
 a beam cantilevered horizontally in the support frame; 
 a damper attached to a free end of the beam and configured to move up and down in response to the air flow, which drives the beam to move up and down accordingly; 
 at least orie PZT layer formed on a surface of the beam, the at least one PZT layer being configured to generate a voltage corresponding to a movement of the beam; and 
 at least one connection pad operably coupled to the at least one PZT layer, the at least one connection pad being suitable for outputting the voltage; 
 wherein distances from the damper to the upper shield and the lower shield are less than those from the beam to the upper shield and the lower shield, respectively; 
 wherein the air flow is related to altitude, 
 wherein the support frame further comprises two side shields, the two side shields respectively connect corresponding end portions of the upper shield and the lower shield, one of the two side shields has a notch formed therein, and an end of the beam opposite the free end is inserted into he notch. 
 
     
     
       2. The altitude sensor of  claim 1 , wherein the damper is bonded to the beam by adhesive. 
     
     
       3. The altitude sensor of  claim 1 , wherein the beam is integrally formed with the damper. 
     
     
       4. The altitude sensor of  claim 1 , wherein the beam comprises a substrate layer formed from a ceramic and/or a metal, and the at least one PZT layer is formed on the substrate layer. 
     
     
       5. An altitude sensor for use in a disk drive device, comprising:
 a support frame having an upper shield and a lower shield opposite the upper shield; 
 a sensor unit mounted in the support frame, the sensor unit comprising: 
 a beam cantilevered horizontally in the support frame ; 
 a damper attached to a free end of the beam and configured to move up and down in response to an air flow generated by a rotating disk, which drives the beam to move up and down accordingly; 
 at least one PZT layer formed on a surface of the beam, the at least one PZT layer being configured to generate a voltage corresponding to a movement of the beam; and 
 at least one connection pad operably coupled to the at least one PZT layer, the at least one connection pad being suitable for outputting the voltage; 
 wherein distances from the damper to the upper shield and the lower shield are less than those from the beam to the upper shield and the lower shield, respectively. 
 
     
     
       6. The altitude sensor of  claim 5 , wherein the support frame further comprises two side shields, the two side shields respectively connect corresponding end portions of the upper shield and the lower shield, one of the two side shields has a notch formed therein, and an end of the beam opposite the free end is inserted into the notch. 
     
     
       7. The altitude sensor of  claim 5 , wherein the damper is bonded to the beam by adhesive. 
     
     
       8. The altitude sensor of  claim 5 , wherein the beam is integrally formed with the damper. 
     
     
       9. The altitude sensor of  claim 5 , wherein the beam comprises a substrate layer formed from a ceramic and/or a metal, and the at least one PZT layer is formed on the substrate layer. 
     
     
       10. A disk drive device, comprising:
 a head gimbal assembly, the head gimbal assembly including a slider formed thereon; 
 a drive arm connected to the head gimbal assembly; 
 a disk, the disk causing an air flow when spun; 
 a spindle motor operable to spin the disk; and, 
 an altitude sensor for adjusting flying height of the slider, the altitude sensor including: 
 a support frame having an upper shield and a lower shield opposite the upper shield; 
 a sensor unit mounted in the support frame, the sensor unit comprising: 
 a beam cantilevered horizontally in the support frame ; 
 a damper attached to a free end of the beam and configured to move up and down in response to the air flow, which drives the beam to move up and down accordingly; 
 at least one PZT layer formed on a surface of the beam, the at least one PZT layer being configured to generate a voltage corresponding to a movement of the beam; and 
 at least one connection pad operably coupled to the at least one PZT layer, the at least one connection pad being suitable for outputting the voltage; 
 wherein distances from the damper to the upper shield and the lower shield are less than those from the beam to the upper shield and the lower shield, respectively. 
 
     
     
       11. The altitude sensor of  claim 10 , wherein the support frame further comprises two side shields, the two side shields respectively connect corresponding end portions of the upper shield and-the lower shield, one of the two side shields has a notch formed therein, and an end of the beam opposite the free end is inserted into the notch. 
     
     
       12. The altitude sensor of  claim 10 , wherein the beam is bonded to the damper by adhesive. 
     
     
       13. The altitude sensor of  claim 10 , wherein the beam is integrally formed with the damper. 
     
     
       14. The altitude sensor of  claim 10 , wherein the beam comprises a substrate layer formed from a ceramic and/or a metal, and the at least one PZT layer is formed on the substrate layer. 
     
     
       15. The disk drive device of  claim 10 , further comprising a processor configured to determine the flying height of the slider over the disk appropriate at a given altitude, a dynamic flying height of the slider over the disk, and an adjustment amount corresponding to the difference between the flying height and the dynamic flying height. 
     
     
       16. The disk drive device of  claim 15 , wherein the processor calculates the altitude according to a formula, the formula being y =−2.29x +115, wherein y is the sensor output in millivolts and x is the altitude in thousands of feet. 
     
     
       17. The disk drive device of  claim 10 , wherein the altitude sensor is located proximate to the disk. 
     
     
       18. The disk drive device of  claim 10 , wherein the altitude sensor is located on a connector of the disk drive device. 
     
     
       19. The disk drive device of  claim 10 , wherein the altitude sensor is located on a top surface of the drive arm. 
     
     
       20. The disk drive device of  claim 10 , wherein the altitude sensor is located on a side surface of the drive arm. 
     
     
       21. The disk drive device of  claim 10 , wherein the altitude sensor is located on a middle region of traces of the head gimbal assembly. 
     
     
       22. The disk drive device of  claim 10 , wherein the altitude sensor is located under the slider. 
     
     
       23. The disk drive device of  claim 10 , wherein the altitude sensor is located near a leading edge of the slider.